单选题 In 1957 a doctor in Singapore noticed that hospitals were treating an unusual number of influenza-like cases. Influenza is sometimes called “flu” or a “bad cold”. He took samples from the throats of patients in his hospital and was able to find the virus of this influenza.
There are three main types of the influenza virus. The most important of these are types A and B, each of them having several sub-groups. With the instruments at the hospital the doctor recognized that the outbreak was due to a virus group A, but he did not know the sub-group. He reported the outbreak to the World Health Organization in Geneva. W. H.O. published the important news alongside reports of a similar outbreak in Hong Kong, where about 15%—20% of the population had become ill.
As soon as the London doctors received the package of throat samples, they began the standard tests. They found that by reproducing itself at very high speed, the virus had multiplied more than a million times within two days. Continuing their careful tests, the doctors checked the effect of drugs used against all the known sub-groups of virus type A. None of them gave any protection. This then, was something new: a new influenza virus against which the people of the world had no ready help whatsoever. Having isolated the virus they were working with, the two doctors now dropped it into the noses of some specially selected animals, which contact influenza in the same way as human beings do. In a short time the usual signs of the disease appeared. These experiments revealed that the new virus spread easily, but that it was not a killer. Scientists, like the general public, called it simply “Asian” flu.
The first discovery of the virus, however, was made in China before the disease had appeared in other countries. Various reports showed that the influenza outbreak started in China, probably in February of 1957. By the middle of March it had spread all over China. The virus was found by Chinese doctors early in March. But China was not a member of the World Health Organization and therefore did not report outbreaks of disease to it. Not until two months later, when travelers carried the virus into Hong Kong, from where it spread to Singapore, did the news of the outbreak reach the rest of the world. By this time it was started on its way around the world.
Thereafter, WHO’s Weekly Reports described the steady spread of this virus outbreak, which within four months swept through every continent.

单选题 The Singapore doctor found the influenza was caused by

【正确答案】 B

【答案解析】[设题点]转折处
[解析] 事实细节题。由第二段第三句话...the doctor recognized that the outbreak was due to a virus group A, but he did not know the sub-group可知，新加坡医生发现此流感是由A型病毒的某个亚型引起的，故答案为[B]。题干中的caused by即为due to之意。[D]为强干扰项，但 [D]是两名伦敦医生得出的结论，是对新流感的定义，而非引起流感的原因，故排除。

单选题 W. H. O, reported the influenza because

单选题 London doctors considered

单选题 The “Asian” flu virus

【正确答案】 C

【答案解析】[设题点] 数字处
[解析] 事实细节题。正确的选项所表达的信息必须在文中能找到确切的“依据”。本题中，[C]为答案，其依据是第三段第二句话…by reproducing itself at very high speed, the virus had multiplied more than a million times within two days。根据第三段第三句话至第五句话排除[A]；根据第四段第三句话排除[B]；第五段第三句话、第七句话和文末最后一句话都能证明[D]错误。